Composition for application of soil-release finish

ABSTRACT

A COMPOSITION FOR APPLYING A NON-PERMANENT SOILRELEASE FINISH TO FABRICS FROM DILUTE SOLUTION COMPRISING A POLYCARRBOXYLATE POLYMER HAVING AN ACID EQUIVALENT WEIGHT O FROM ABOUT 110 TO 175, AAND A WATER-SOLUBLE SALT OF A POLYVALENT METAL. A PREFERRED POLYCARBOXYLATE POLYRELEASE FINISH TO FABRICS FROM DILUTE SOLUTION COMPRISING MER IS A COPOLYMER OF 2/3 METHACRYLIC ACID AND 1/3 ETHYLACRYLATE. THE COMPOSITION IS PARTICULARLY USEFUL FOR APPLYING A SOIL-RELEASE FINISH IN THE RINSE CYCLE OF A HOME LAUNDRY PROCESS.

3,798,169 COMPOSITION FOR APPLICATION OF SOIL-RELEASE FINISH Robert E.Dickson, Belle Mead, N.J., and Stanley M. Barkin, Pittsburgh, Pa.,assignors to Colgate-Palmolive Company, New York, N.Y. N Drawing. FiledApr. 28, 1972, Ser. No. 248,658

Int. Cl. Clld 7/22 US. Cl. 252-89 13 Claims ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION This invention relates to a composition fortreating a textile substrate to impart a soil-release characteristicthereto which can be conveniently used in the rinse cycle of a homelaundry procedure.

The genesis of synthetically produced textile fibers has brought about atremendous effort in the textile industry along numerous avenues. Therehas been much research effort directed to the improvement of thesesynthetic fibers per se, and improved blends of synthetically producedfibers with natural fibers, i.e., cellulosic fibers or keratinousfibers. Results of this research have been successful and the directionof research has been diverted from the synthetic polymer per se and/orblends of said polymers with other naturally occurring fibers. Recently,fiber research has been directed towards improving physicalcharacteristics of fabric produced from synthetic fibers and/ or blendsof these synthetic fibers with naturally occurring fibers, and, morespecifically, to the physical characteristics and/or enduranceproperties of garments produced from synthetic fabrics and/or fabricproduced from blends of synthetic fibers and naturally occurring fibers.

Much research has been directed to the attainment of a garment havingimproved soil-release properties. Many of the synthetically producedfibers that are presently being incorporated in blends with naturallyoccurring fibers have a propensity to accept and retain oily grime anddirt. Accordingly, when the garmet is being worn the soil and/or oilymaterials accumulate on the garment and settle in the fabric. Once thegarment becomes soiled, it is then subjected to a cleaning process forremoval of the dirt and/or oily deposits, and only a dry cleaningprocess will successfully clean the garment.

The cleaning process normally employed, however, is washing in aconventional home washing machine by the housewife. During a wash cycle,it is virtually impossible to remove the soil and/or oily stains fromthe garment and, secondly, assuming that the undesirable materials areremoved from the garment or a fairly clean garment is being washed, soilremaining in the wash water is redeposited onto the garment prior to theend of the wash cycle. Hence, when the garment is removed from thewashing machine and subsequently dried, it has not been properlycleaned. Such a condition, heretofore unavoidable, is quitedisadvantageous in that the garment after being worn never again assumesa truly clean appear- "United States Patent 0 3,798,169 Patented Mar.19, 1974 ance, but instead tends to gray and/or yellow due to the soiland/or oily materials deposited and remaining thereon. Further use andwashing of the garment increases the intensity of the graying to thepoint that ultimately the garment is unacceptable for further wear dueto its discoloration. The process of the present invention solves thesoiling problem as hereinafter described.

The problem heretofore confronted with fabrics having synthetic fibersincorporated therein, or made entirely of synthetic fibers, has beenthat the synthetic fibers, as well as being hydrophobic, are oleophilic.Therefore, while the oleophilic characteristics of the fiber permit oiland grime to be readily embedded therein, the hydrophobic properties ofthe fiber prevent water from entering the fiber to remove contaminantstherefrom.

Attempts have been made to reduce the oleophilic characteristics ofthese synthetic fibers by coating the fibers with a coating that isoleophobic, i.e., will hinder the attachment of soil or oily materialsto the fiber. Many polymer systems have been proposed which are capableof forming a film around the fibers that constitute the textilematerial, particularly acid emulsion polymers prepared from organicacids having reactive points of un saturation. These treating polymersare known as soilrelease agents.

The term soil-release in accordance with the present invention refers tothe ability of the fabric to be washed or otherwise treated to removesoil and/or oily materials that have come into contact with the fabric.The present invention does not wholly prevent the attachment of soil oroily materials to the fabric, but hinders such attachment and rendersthe heretofore uncleanable fabric now susceptible to a successfulcleaning operation. While the theory of operation is still somewhat of amystery, soiled, treated fabrics when immersed in detergent-containingwash water experience an agglomeration of oil at the surface. This wateris basic in nature, and it has been determined that soil-release is bestrealized in wash water that is basic in nature. These globules of oilare then removed from the fabric and rise to the surface of the washwater. This phenomenon takes place in the home washer during continuedagitation, but the same effect has been observed even under staticconditions. In other words, a strip of polyester/cotton fabric treatedwith a dilute aqueous solution of the composition of the presentinvention and soiled with crude oil, when simply immersed in a detergentsolution will lose the oil even without agitation.

Concentrated solutions of soil-release polymers have been padded ontofabrics to impart a permanent soilrelease finish to the fabrics. As theamount of soil-release polymer on the fabric is increased, the abilityof the fabric to release soil is increased. However, fabrics with thispermanent soil-release finish possess many disadvantages. As the amountof soil-release polymer on the fabric is increased, the fabric has atendency to become stiffer and lose the desirable hand characteristic ofthe fabric. Thus, the upper limit on the amount of soil-release polymeris determined by economics and the resulting adverse effect on thefabric, i.e., the hand of the fabric. Fabrics with a relatively heavyapplication of soil-release polymer do not have the same desirableappearance and hand as the fabrics without the soil-release polymer.Furthermore, practically speaking, there is a set range of soil-releaseagent that can be applied, dictated by commercial success.

Some soil-release polymers are effective fabric treating agents even atvery low levels on the fabric, at which levels the appearance and handof the fabric are not adversely affected. Thus, an ideal method oftreating a synthetic fiber-containing fabric would be to reapply a verysmall amount of soil-release polymer each time the fabric is washed,such as in the rinse cycle of a home laundry procedure.

Certain polycanboxylate polymers are very effective soil-release agentsat low levels on the fabric. However, they cannot be applied to fabricsfrom dilute aqueous solutions because the polymers are so soluble inwater that they will not deposit onto the fabric from dilute solutions.

SUMMARY OF THE INVENTION It has now been discovered that a veryeffective nonpermanent soil-release finish can be applied to fabricsusing a dilute aqueous solution of a polycarboxylate polymer in thepresence of a water-soluble salt of a polyvalent metal. The polyvalentmetal salt serves to decrease the solubility of the polymer sufficientlyto cause the polymer to be deposited onto the fabric from dilute aqueoussolution. The ratio of metal salt to the copolymer ranges from 1:5 to20: 1.

Polycarboxylate polymers found to be effective soilrelease agents whenapplied from dilute solution in the presence of a polyvalent metal saltare those polycarboxylate polymers having an acid equivalent weight(i.e., gram per mole of carboxylate) in the range of from about 100 to175. The preferred acid equivalent weight for these polymers for use inthis invention is about 125.

The most eflFective polymers for use as soil-release agents applied fromdilute solution in the presence of water-soluble polyvalent metal saltsare copolymers of methacrylic acid with ethylacrylate wherein themethacrylic acid comprises about /a of the copolymer and theethylacrylate comprises about /3 of the copolymer. The methacrylicacid/ethylacrylate copolymers that are effective have molecular weightsranging from about two thousand to about five million, althoughcopolymers having a molecular weight of about one million are preferred.The copolymers form a hydrophilic film on the treated fibers upondrying, and afford soil releasability at that point. Each subsequenttreatmentwith the polymer serves to enhance the soil-releasecharacteristics of the substrate.

The polyvalent metal salts found to be particularly effective in thepractice of this invention are the watersoluble salts of calcium andmagnesium, such as calcium chloride, calcium sulfate, calcium nitrate,calcium acetate, magnesium chloride, magnesium sulfate, magnesiumnitrate, and magnesium acetate. Other polyvalent metal salts that can beused effectively include the water-soluble salts of zirconium, tin,aluminum, zinc, and barium. Specific examples of these salts includezirconium oxychl'oride, stannic chloride, aluminum sulfate, zincchloride, and barium acetate. The metal salts can be present insolutions of compositions in amounts ranging from about 0.001% to about1.0%, although a range of from about 0.01% to about 0.20% is preferred.

The ratio of polyvalent metal salt to polycarboxylate polymer of thepresent invention ranges from about 1:5 to about 20:1 although a rangeof about 1:5 to about 4:1 is preferred.

The compositions can be effectively used in aqueous solution at between0.01% to 0.10%, and are effective at pH ranges between 4.5 and 9.5. Thecompositions are thus particularly effective for use in the rinse cycleof the home laundry process, for imparting a temporary soilreleasefinish to fabrics as soon as the fabrics are washed.

The soil-release properties of pure cellulosic fiber fabrics are muchbetter than those of synthetic fiber containing fabrics, e.g., polyesterfibers, in that the synthetic polyester fibers are hydrophobic and thusprevent the ingress of water that is necessary for cleaning the fabric,and also possess an electrical charge that attracts soil particles. Thepresent invention is therefore most primarily directed to fabricscontaining a substantial portion of synthetic polyester fibers.

The present composition may be used to treat a wide variety of textilematerials made exclusively from synthetic polymer fibers, as well asblends of natural and synthetic fibers. Examples of synthetic fiberswhich may be successfully employed in the practice of the presentinvention include those made with polyamide, acrylic, and polyesterfibers. Blends of natural and synthetic fibers which may be successfullytreated according to the present invention include fabrics comprising50% polyester/50% cotton, 65% polyester/35% cotton, etc. Cellulosefibers, for example, cotton, viscose, regenerated cellulose, etc., alsomay be combined with the synthetic fibers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example I Soil-releasecompositions were formulated using a copolymer of about methacrylic acidand about /3 ethylacrylate, having a molecular weight of about onemillion, and the percentage of a divalent metal salt as shown in TableI.

TABLE I Composition: Salt and concentration A 0.1% MgCl B 1% MgCI C 0.1%CaCl D 1% CaCl E 0.2% Ba acetate.

F 0.14% ZnCl Aqueous treating solutions 'were made up using 0.05% byweight of the copolymer and the salt concentration listed; the pH ofthese compositions was about 5. Prewashed swatches of 65% polyester/35%cotton with a permanent press finish were soaked for 10 minutes in thetreating solution and allowed to dry.

Three drops of 1:1 used motor oil/mineral oil were dropped into thecenter of each of the swatches, and the oil was allowed to spread andset for three hours. The swatches were then washed in a solution of 1.5g./liter of a 10-2-2 (anionic-nonionic-soap) commercially availablehousehold laundry detergent for ten minutes at F., and rinsed for fiveminutes.

Table IV shows the final reflectance value, in Rd. units, of theswatches. The control received no soil-release treatment prior to beingsoiled with the oil mixture.

Soil-release compositions were formulated using the copolymer of ExampleI and the following concentrations of the following salts.

TABLE III pH of S alt and coneentratreating tron solution Swatch:

Treating solutions were made up using 0.05% by weight of the copolymerand the salt concentration listed; the pH of each solution is shown inTable III. Identical prewashed swatches of 65% polyester/ 35 cotton witha permanent press finish were soaked for minutes in the treatingsolution and dried in a dryer.

'Ihree drops of 1:1 used motor oil/mineral oil were dropped into thecenter of each of the swatches, and the oil was allowed to spread andset for three hours. The swatches were then washed in a solution of 1.5g./liter of a 10 2-2 (anionic-nonionic-soap) commercially availablehousehold laundry detergent for ten minutes at 80- 90 F., and rinsed forfive minutes.

Table IV shows the final reflectance value, in Rd. units, of theswatches. The control received no soil-release treatment prior to beingsoiled with the oil mixture.

The foregoing examples illustrate the efiectiveness of a compositioncomprising a methacrylic acid and V3 ethylacrylate copolymer and a metalsalt as a soil-release agent when deposited from dilute solution.

The compositions of the present invention are particularly well adaptedfor use in the rinse cycle of a home laundry system; the compositionscan be added directly to the rinse water without adjusting the pH or thetemperature of the water.

None of the swatches treated in the foregoing examples had chunks ofpolymer visible on the surface of the swatches, and the original hand ofthe fabrics was not adversely afiected by the treatment with thesoilrelease polymer of the present invention.

What is claimed is:

1. A composition for imparting non-permanent soilrelease characteristicsto a textile material comprising a copolymer consisting of aboutmethacr'ylic acid and /s ethylacrylate; having an acid equivalent weightof about 110 to about 125, and having a molecular weight of about twothousand to about two million, and a water-soluble salt of a polyvalentmetal operative to lower the solubility of said copolymer and therebyenhance deposition thereof onto said material and being selected fromthe group cons sting of magnesium, calcium, zirconium, tin, aluminum,zinc, and barium, the ratio of said salt to said copolymer being in therange of about 1:5 to about 20:1.

2. The composition of claim 1 wherein said salt is a calcium salt.

3. The composition of claim 1 wherein the ratio of said polyvalent metalsalt to said copolymer is from 1:5 to 4:1.

4. The composition of claim 1 wherein the salt is a magnesium salt.

5 The composition of claim 1 wherein the salt is magnesrum. chloride.

6. The composition of claim 1 wherein the copolymer has a molecularweight of about one million.

7. The composition of claim 1 wherein the salt is calcium chloride.

8. A dilute aqueous solution of the composition as defined in claim 1containing about 0.01 to about 1.0% by weight of said composition.

9. A solution as defined in claim 8 having a pH in the range of about4.5 to about 9.5.

10. A solution as defined in claim 8 containing about 0.001 to about1.0% of said salt.

11. A soil resistant synthetic fiber-containing material having aneifective amount of the composition as defined in claim 1. 12. Amaterial as defined in claim 11 wherein said fiber is selected from thegroup consisting of polyester, polyamide, acr'ylic, cellulose, cotton,viscose and regenerated celluose.

'13. A method of rendering synthetic fiber-containing materials soilresistant comprising applying thereto an effective amount of a solutionas defined in claim 8.

References Cited UNITED STATES PATENTS 2,999,774 9/1961 Schappel117--139.5 CF 3,377,249 4/1968 Marco 117- 1395 CF 3,574,620 4/1971Tesoro 1=17139.5 CF 3,658,570 4/1972 Crooks et al. .117139.5 R 3,671,2926/1972 Hirschfield et al.

WILLIAM E. SCHUIZ, Primary Examiner US. Cl. X.R.

